Arrangement and method for the production of mats or similar flat formations of mineral wool



May 26, 1959 ARRANGEMENT AN D METHOD FOR THE PRODUCTION OF MATS FiledMay 20, 1957 s 0. K. KJELL-BERGEl Q OR SIMILAR FLAT FORMATIONS OFMINERAL WOOL 2 Sheets-Sheet l Y 1a J ATTORNEYS 2 ,888,060 2 SheetSheet 2y 1959 s. 0-. K. KJELL-BERGER ARRANGEMENT AND METHOD FOR THE PRODUCTIONOF MAT 0R SIMILAR FLAT FORMATIONS 0F MINERAL WOOL Flled May 20, 1957United States Patent ARRANGEMENT AND METHOD FOR THE PRO- DUCTION OF MATS0R SIMILAR FLAT FORMA- TIONS .OF MINERAL WOOL Sven Olof KjellKjell-Berger, Skovde, Sweden, assignor to Rockwool Akfiebolaget, Skovde,Sweden, :1 corporation of Sweden Application May 20, 1957, Serial No.660,278

Claims priority, application Sweden May 23, 1956 9 Claims. (01. 154-27Mats of spun mineral wool are employed, particularly within the buildingindustry, for a variety of insulation purposes. The mats are commonlybound together with sewing, the body of the mat comprising mineral woolspun from glass fiber, from molten stone, or similar material. In theproduction of the mats, fine fibrous particles are spun from a machinewhich uses the mineral in molten form to spin a mass of particles whichare known in bulk as mineral wool. The fibrous particles are extrudedupon a slowly moving conveyor on which they are compressed into a mat,enclosed between two strips of impregnated paper, the strips being sewntogether to form the bound mat.

The mass of mineral particles is also commonly subjected to treatmentwith an oil of low volatility, with a plastic resin, or some otherbinding material which is intended to impregnate and bind the particlesinto a more coherent mass.

Difliculty has arisen in the manufacture of these mats, however, inassuring that the bound mats Will have a constant or substantiallyconstant volume weight. The mineral material to be used in spinning thefibrous particles is normally molten into a thin liquid consistency. Toaccomplish this, a cupola furnace is often used. The ovens are chargedin layers of the mineral and of the fuel. As the fuel burns, the mineralcharge becomes molten, Stratification takes place, and the charge isreleased in the form of a thin jet Within the spinning machine. Thequantity of mineral charge supplied to the spinning machine for unit oftime is dependent upon conditions within the furnace, such as the amountof charge in a molten state as compared with that remaining in asomewhat semi-molten state. Other conditions are also significant, suchas unevenness in the original charge which causes irregularity in thesupply of molten material to the spinning machine.

Because of these difficulties, and because of the variance in theamounts of fibrous material extruded from the spinning machine, asomewhat heterogeneous final product is obtained. Although the mineralWool mass is subjected to compression and the thickness of the wool matcan be standardized accordingly, the insulative power, the volumeweight, and the resiliency of the mat will nevertheless vary along thelength of the mat on the conveyor.

Variations in these characteristics of the mat are observed to occur inrelation to the feed of molten material to the spinning machine. Whilethese variations can be somewhat counteracted by adjustingcorrespondingly the speed of the conveyor collecting the mineral wool,manual control of the speed is scarcely possible as one cannot observeby eye any particular phenomena which make it possible to judge whetherthe speed of the conveyor needs to be increased or decreased. Nor canthe speed of the conveyor be controlled on the basis of the weight ofmineral wool deposited. For at the time when an increase in the speed ofthe conveyor would be necessary, already an excess of mineral wool wouldhave been deposited. And where aldecrease in theamount of wooldeposited"Ice occurred, it would not be-possible at a later time to account forthe dilference by some means; involving reasonable costs and time.

According to the instant invention, the aforementioned disadvantages areovercome by regulating the speed of the conveyor in relation to thepower consumed by the spinning machine. The invention is predicated uponthe observation that the power consumed by the spinning machine variesin accordance with the quantity of mineral wool extruded by the machine.Variances in power consumption are of such magnitude as to permit theirmeasurement and the regulation of the speed of the conveyor accordingly.

Thus, by the method described herein the volume weight of the mineralwool mat per unit length of the conveyor is maintained at asubstantially constant value.

In a preferred embodiment, the control apparatus for regulating thespeed of the conveyor in relation to the power consumed by the spinningmachine is mounted along the feeder circuits leading to the electricalpower means for the spinning machine. The invention will become moreevident from the following description, to be read in connection withthe attached drawings, wherein this preferred embodiment is set forth.

In the drawings, Figure 1 shows diagrammatically the overall arrangementof the invention. Figure 2 shows, diagrammatically also, an arrangementofthe speed control means as indicated at 31 in Figure 1.

It is to be understood that the instant invention is not limited to usewith any one kind of spinning machine. Many different kinds of spinningmachines, tested in accordance with the present invention, havedemonstrated the property of their power consumption varying closelylinearly with the amount of mineral wool extruded from the spinningmachine per unit of time. As described herein, the invention is appliedin connection with a spinning machine having rotating wheels, from thesurface of which the mineral is expelled in the form of wool particles.But the invention is nevertheless applicable 'with all kinds of spinningmachines which are commonly employed in practice'for the production ofmineral wool.

The invention also contemplates simultaneous control of the feed of themany kinds of impregnating materials, or the various other operationswhich etfect the uniformity of the wool mat.

In the drawings it can be seen that 10 indicates a cupola furnace inwhich the mineral is melted down to be spun into the wool. The mineralis charged in layers 11, 12, and 13, alternate to layers of fuel 14, 15,and 16. Forced air is fed through an inlet 17 for supporting combustion.A melt 18 is collected in the bottom of the furnace and released throughoutlet 19 in the form of a freely falling jet 20.

The jet 20 falls into the spinning machine generally indicated at 21.According to the particular embodiment described herein, the spinningmachine 21 comprises a number of wheels which rotate with differentspeeds. The wheels are so arranged that the jet 20 hits a first wheelmoving at a low speed, from which the melt is thrown over to a secondwheel moving at a higher speed, and finally to a third wheel moving at astill higher speed. Only the first and third wheels are visible inFigure 1 at 22 and 23, respectively.

The spinning machine 21 may be driven by a single motor or by aplurality of motors. In Figure l the machine is driven by two separatemotors 24 and 25, motor 24 driving the spinning wheel 22 and the secondspinning wheel not shown in the figure, over a power transmission 26,the second motor 25 driving the third spinning wheel 23 over a powertransmission 27 r 'The motors themselves are actuated through3-phase'current over feeding lines 28 and 29 which in turn are fed froma main 30through assaoeo the control apparatus 31, which is dealt withingreater detail in Figure 2.

The control apparatus 31 functions so as to measure the amount of powerfed over the conduits 28 and 29 to the motors 24 and from the main 3%.In relation to this power value, control apparatus 31 regulates thevoltage value or some other suitable value on an output control conduit32, over which a motor 33 is fed with current from a direct currentnetwork 34.

From the spinning wheels, or at least from the last of the spinningwheels 23, a cascade of spun mineral wool 35 is deposited on a conveyor36 moving in the direction of the arrow 37 under the influence of themotor 33. A mat 38 of mineral Wool is built up on the conveyor 36, andthe resultant mat is compressed by means of a loaded roller 39. Justbeyond, the compressed mat is transferred to a second conveyor 40 driventhrough a power transmission not shown in the drawing synchronously withthe conveyor 36. Belt driving may be arranged between the shaft for thelast support roller 41 of the first conveyor 36 and the first supportroller 42 of the second conveyor The formed mineral wool mat istransferred to the second conveyor ll with constant thickness andwithout any tendency to displace in a horizontal direction such that itwould be further compressed or torn apart. Conveyor 40 carries the woolmat to a point where the later operations for forming the bound mat areaccomplished. These operations do not form any part of the instantinvention.

Control apparatus 31 functions so as to regulate the speed of the motor33 in relation to the consumption of power of the motors 24 and 25driving the spinning machine 21. Motor 33 drives the conveyor 36 andindirectly the conveyor 46. Regulation of the speed of the conveyoroccurs in such a way that the rate at which the mat 38 builds up on theconveyor is adapted to the quantity of mineral wool deposited from thespinning machine such that after compression to a uniform thickness themat 38 will also have a substantially constant volume weight.

Binder material is also introduced in the spinning machine to themineral wool mass. Moreover, the amounts of binder material fed to themass are similarly fed in relation to the power consumption of thespinning machine. Normally the binder material is fed as a showerdistributed through the hollow shafts of the spinning t /heels 22 and23. In the arrangement according to Figure 1, the material is fed tothese shafts at their left end by means of flexible piping 43 and 44,the pipes themselves being fed by means of a pump 45 driven by the motor46. The speed of the motor 46 is also regulated oil of the outputcontrol. conduit 32.

A preferred embodiment of the control apparatus 31 itself shall now bedescribed with reference to Figure 2.

Schematically shown at 47 is a 3-phase motor, which may be the onlymotor or one of several motors driving the spinning wheels. The motor 47is fed with current over the 3-phnse conductor 48 which representsschematically the 3-phase conductors 28 and 29 shown in Figure l. Theprimary winding of a current transformer $9 is connected into one of thephase conductors, and the secondary winding is connected to the workerwinding 50 of an ampere metrical control instrument, the pointer 52 ofwhich is turnable about the shaft 51. The pointer 52 supports a screen53 of an appropriate arc length. This screen is positioned between twodiscs 54 and 55 which are turnable about a shaft 51" co-axial with theshaft 51 but mechanically free from shaft 51'. Each of the discs 54 and55 contains an arc-shaped slot or opening 56 and 57 respectively, thearc radius of the slots being substantially the same as that of thescreen 53. On the far side of the disc 55 are two sources of lighthaving optics 60 and 61 directing concentrated beams of lightperpendicular to the disc 54 and 55 and to the screen 53.- Normally thescreen 53 lies in the path of these beams of light such that the beamsare prevented from striking a pair of photoelectric cells 58 and 59.When, through the action of the ampere metrical instrument, the screen53 is displaced to one side or the other, either the beam of light fromthe source '69 will hit the photoelectric cell 53 or the beam fromsource 61 will hit the photoelectric cell 59.

The photoelectric cells 58 and 59 are each connected to one of a pair ofDC. current amplifier electronic tubes 62 and 63 which straddle a commonbias battery 64 connected into the grid-cathode circuit, or some othersuitable source of bias voltage of such a magnitude that when thephotoelectric cells are unstimulated, the electronic tubes will benon-conductive. In the anode circuit of the tubes 62 and 63 are relays65 and 66, respectively, connected to be actuated when the electronictubes become conductive. A reversible motor 67, for the sake ofsimplicity drawn as a direct current motor with two magnetizing windings68 and 69 coupled in opposite directions, is connected to the mains overone of the contacts 70 and 71 on the relays 65 and 66 such that themotor will rotate in one direction when the tube 62 is conductive andthe relay 65 is actuated. The motor 67 will rotate in the oppositedirection when the tube 63 is conductive and the relay 66 is actuated.Through a gear 7%" with a large gear ratio the motor 67 is connected tothe transmitter '71" in a Selsyn system, the three condoctor system ofwhich is indicated at 72. This three conductor system feeds twodifferent motors, first, a Selsyn motor 73 which through a gear 74 turnsthe discs 54 and 55, and second, a second Selsyn motor 75 which througha worm gear 76 sets a speed control resistor 77 and 78 for the motor 33.The motor 33 is that shown in Figure l for driving the conveyor 3640.The shaft of the worm gear 7 6 is combined with a control arm 77 for thespeed control resistor 78 which is connected in the circuit of the motor33.

The foregoing arrangement functions in the following manner: When theamount of mineral wool expelled from the spinning wheels increases forone reason or another, the motors indicated schematically in Figure 2 by47 are loaded more heavily. This load increase results in an increasedvoltage in the secondary winding of the transformer 49 whereby thepointer 52 of the ampere metrical instrument is moved in a clockwisedirection. Consequently, the screen 53 is displaced in such a way thatthe light beam from the light source 60 strikes the photoelectric cell58 and the tube 62 becomes conductive. T he relay 65 is thus actuated,its contact 7% is closed, and the servomotor 67 is activated in such adirection to change the angular position of the transmitter of theSelsyn system and its two receivers, bringing the arrangement intobalance once more. The receiver 75 is turned in such a direction thatthe resistance 78 is decreased whereby the speed of the motor 33 isincreased correspondingly. The receiver 73 simultaneously is turned insuch a direction that the discs 54 and 55, together with the lightsources 60 and 61 and the photoelectric cells 58 59, are reset in thedirection in which the arm of the pointer of the ampere metricalinstrument had been turned the moment before. This movement continuesuntil both of the light beams are again screened by screen 53, the tube62 thus becoming non-conductive once more, the relay 65 being released,the contact 7 0 opening again, the motor 67 stopping, and the Selsynsystem having again resumed a state of balance. In result, however, themotor 33 will rotate with a somewhat higher speed corresponding to thehigher consumption of power by the spinning Wheel motors and theincreased quantity of spun mineral wool deposited on the conveyor, suchthat the volume weight of the mineral wool mat remains substantiallyconstant at all times along the length of the conveyor.

On the other hand, if the consumption of power by the spinning wheelmotors decreases, simultaneous with a corresponding decrease in theamount of spun mineral wool ejected by the spinning wheels, theoperation occurs in a somewhat opposite fashion. The beam of light fromthe light source 61 strikes the photoelectric cell 59, the tube 63becomes conductive, and the relay 66 is actuated. The motor 67 rotatesin a direction opposite to that occurring with an increase inconsumption, and the whole Selsyn system is activated in the oppositedirection. The resistor 78 is reset in such a direction that the motor33 undergoes a decrease in speed, and the discs 54 and 55 are turned inthe opposite direction until the screen 53 again obstructs the beam oflight from the light source 61 such that it does not reach the photoelectric cell 59. Thereafter, the whole arrangement assumes a state ofbalance adapted to the new speed of feeding the spun mineral wool to theconveyor.

Although the invention has been described in considerable detail withreference to certain preferred embodiments thereof, it will beunderstood that variations and modifications can be efiected withoutdeparting from the spirit and scope of the invention as describedhereinabove and as defined in the appended claims.

What is claimed is:

l. A method of producing mats of mineral wool having substantiallyconstant volume-weight comprising the steps of feeding a molten mineralmass to a spinning machine, allowing the spun wool particles to bedeposited on a conveyor, uniformly compressing the mass of particlesthus deposited, and controlling the speed of said conveyor in relationto the variations in power consumed by the spinning machine such thatthe volume-weight of wool per unit length of said conveyor remainssubstantially constant.

2. A method according to claim 1 further including the step ofcontrolling the amount of binding material fed to said machine inrelation to the power consumed by said machine.

3. A method according to claim 1 wherein said spin ning machine ispowered by electrical means and control of the speed of said conveyor iseffected by means provided in the feeder circuits to said electricalmeans.

4. An arrangement for producing mats of mineral wool havingsubstantially constant volume-weight comprising means for producing amolten mineral mass, a

machine for spinning mineral wool particles from said mass, means forpowering said machine, a conveyor for catching and collecting the spunwool particles emanating from said machine, means for driving saidconveyor, means for uniformly compressing the mass of particlescollected on said conveyor, and means for regulating the speed of saidconveyor in relation to the power consumed by said machine such that thevolume-Weight of wool per unit length of said conveyor remainssubstantially constant.

5. An arrangement according to claim 4 further comprising means forfeeding binding material to said machine, said regulating means alsoregulating the amounts of said material fed to said machine in relationto the power consumed by said machine.

6. An arrangement according to claim 4 wherein said powering means iselectrically actuated and said regulating means is placed in the feedercircuits to said powering means.

7. An arrangement according to claim 6 wherein said driving means iselectrically actuated, said regulating means comprising means formeasuring fluctuations in current through said feeder circuits, andmeans for controlling the voltage across said driving meanscorresponding to said fluctuations.

8. An arrangement according to claim 7 wherein said control meanscomprises at least one light source, at least one photoelectric cell,means for preventing light from said source from reaching said cell,said preventing means being displaceable by said measuring means, andmeans for adjusting the resistance in-the feeder circuits for saiddriving means when said preventing means is displaced.

9. An arrangement according to claim 8 wherein said last named meansalso includes means for realigning said preventing means with saidsource and said cell so as to prevent light from reaching said cellagain.

References Cited in the file of this patent UNITED STATES PATENTS2,305,516 Coss et a1 Dec. 15, 1942 2,450,914 Powell Oct. 12, 19482,561,843 Coleman July 24, 1951

